Endangered Status The Yuma Clapper Rail, a subspecies of the Clapper Rail, is on the U.S. Endangered Species List. It is classified as endangered in California and Arizona. Although it is still common in the East, the Clapper Rail has become endangered in the western United States because of the gradual destruction of its habitat. The freshwater Yuma subspecies, with a population containing only several hundred birds, lives along the lower Colorado River of California, Arizona, and Mexico, where water management practices threaten its safety.